Chapter reviewed and updated in December 2017. A description of changes can be found at Updates to the Communicable Disease Control Manual.


New Zealand Epidemiology

Delta hepatitis (hepatitis D, HDV) may occur as an acute co-infection with hepatitis B or as a super-infection in people with chronic hepatitis B infection.

Hepatitis E (HEV) is an enteric infection with a similar course to hepatitis A.

Hepatitis G is usually associated with chronic hepatitis B or hepatitis C infection or human immunodeficiency virus (HIV). There is little proof that hepatitis G (HGV) causes serious liver disease at any age. It is possible that HGV may not be a true ‘hepatitis’ virus.

More detailed epidemiological information is available on the Institute of Environmental Science and Research (ESR) surveillance website.

Case definition

Clinical description

An illness with variable symptoms including fever, malaise, anorexia and nausea with jaundice and/or elevated serum aminotransferase levels. Hepatitis G has no recognised disease sequelae.

Laboratory test for diagnosis

Laboratory definitive evidence for a confirmed case requires negative tests for hepatitis A and C, and one of:

  • a positive anti-HDV test or detection of HDV nucleic acid
  • a positive anti-HEV test or detection of HEV nucleic acid
  • a positive test for hepatitis G.

Hepatitis D requires simultaneous hepatitis B co-infection; testing for hepatitis D is indicated in clinically severe cases of suspected hepatitis B.

Case classification

  • Under investigation: A case that has been notified, but information is not yet available to classify it as probable or confirmed.
  • Probable: Not applicable.
  • Confirmed: A clinically compatible illness accompanied by laboratory definitive evidence.
  • Not a case: A case that has been investigated and subsequently found not to meet the case definition.

Spread of infection


Hepatitis E: Humans are natural hosts; HEV strains have been detected in pigs, deer, sheep, cattle, rats and rabbits.

Incubation period

  • Hepatitis D: 2–8 weeks.
  • Hepatitis E: 15–64 days.
  • Hepatitis G: Not known.

Mode of transmission

Depends on the causative virus. Consult with ESR and infectious diseases physician.

Period of communicability

Depends on the causative virus. Consult with ESR and infectious diseases physician.


Notification procedure

Attending medical practitioners or laboratories must notify the local medical officer of health of probable or confirmed cases.

See Appendix 5: Escalation pathways for more information

Management of case


Obtain a history of travel (including contact with overseas visitors within the incubation period), vaccination, possible contacts, consumption of shellfish or other suspect foods (for example, food from other countries) and blood or blood-product transfusions. Injecting drug users and men who have sex with men may be at higher risk of infection.

Ensure laboratory confirmation has been attempted.


Depends on the causative virus. Consult with ESR and infectious diseases physician.


Depends on the causative virus. Advise the case and their caregivers of the nature of the infection and its mode of transmission. Educate about hand hygiene and advise not to prepare or handle food for others until no longer considered infectious.

Management of contacts


Depends on the causative virus. Consult with ESR and infectious diseases physician.


Laboratory screening of asymptomatic contacts is not usually indicated. Consider blood tests for any contact with compatible symptoms.


Depends on the causative virus. Consult with ESR and infectious diseases physician.


Depends on the causative virus. Consult with ESR and infectious diseases physician.

Other control measures

Identification of source

Check for other cases in the community. Investigate potential food and water sources of infection if there is a cluster of cases or an apparent epidemiological link.

If indicated, check water supply for contaminants and for compliance with the latest New Zealand drinking-water standards (Ministry of Health 2008). Liaise with the local territorial authority staff to investigate potential water sources of infection.


Clean and disinfect surfaces and articles soiled with stool. For further details, refer to Appendix 1: Disinfection.

In areas with modern and adequate sewage disposal systems, faeces and other bodily fluids or secretions can be discharged into sewers.

Health education

If there is a cluster of cases, consider a media release and direct communication with local parents, early childhood services, schools and health professionals to encourage early reporting of symptoms. In communications with doctors, include recommendations regarding diagnosis, treatment and infection control.

In early childhood services or other institutional situations, ensure that satisfactory facilities and practices are in place for: hand cleaning; nappy changing; toilet use and training; food preparation and handling; and cleaning of sleeping areas, toys and other surfaces.


National reporting

Ensure complete case information is entered into EpiSurv.

Where food/food businesses are thought to be involved inform the Ministry for Primary Industries.

If a cluster of cases occurs, contact 0800GETMOH - CD option, and outbreak liaison staff at ESR, and complete the Outbreak Report Form.

Further information


  • Ministry of Health. 2008. Drinking-water Standards for New Zealand 2005 (Revised 2008). Wellington: Ministry of Health.